How can I keep my culture medium from becoming alkaline while in the bottle?
Unopened bottles of medium never turn alkaline. It seems CO2 escapes when you open the bottle too often. Try to buy smaller bottles, like 500 ml. Some people add HEPES buffer to their medium. It never concerns me. The fresh medium changes to neutral pH after a short while inside the CO2 incubator. You may try to warm up your bottle of medium with cap loose in the CO2 incubator instead of water bath.
